Current design of ophthalmic lenses and particularly of progressive lenses does not take into account the natural convergence ability specific to each individual. It supposes indeed that the object accommodation plane perfectly corresponds to the convergence plane.
However, it is not rare to observe a shift between these two planes due to a delay of convergence for example. This shift can lead to visual fatigue and discomfort symptoms, such as blurred vision and headaches for example.
Dynamic measurement of convergence amplitude enables to quantify the natural ability of an individual and to characterize such a shift. Besides, it can also highlight an oculomotor dyssynergia, one eye being faster than the other.
Starting from this situation, an object of the present invention consists in efficiently taking into account the existence of a difference between the convergence plane and the object accommodation plane such as a convergence delay when designing a progressive surface.